1 /* 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef COMMON_VIDEO_H264_SPS_PARSER_H_ 12 #define COMMON_VIDEO_H264_SPS_PARSER_H_ 13 14 #include "absl/types/optional.h" 15 #include "rtc_base/bitstream_reader.h" 16 17 namespace webrtc { 18 19 // A class for parsing out sequence parameter set (SPS) data from an H264 NALU. 20 class SpsParser { 21 public: 22 // The parsed state of the SPS. Only some select values are stored. 23 // Add more as they are actually needed. 24 struct SpsState { 25 SpsState(); 26 SpsState(const SpsState&); 27 ~SpsState(); 28 29 uint32_t width = 0; 30 uint32_t height = 0; 31 uint32_t delta_pic_order_always_zero_flag = 0; 32 uint32_t separate_colour_plane_flag = 0; 33 uint32_t frame_mbs_only_flag = 0; 34 uint32_t log2_max_frame_num = 4; // Smallest valid value. 35 uint32_t log2_max_pic_order_cnt_lsb = 4; // Smallest valid value. 36 uint32_t pic_order_cnt_type = 0; 37 uint32_t max_num_ref_frames = 0; 38 uint32_t vui_params_present = 0; 39 uint32_t id = 0; 40 }; 41 42 // Unpack RBSP and parse SPS state from the supplied buffer. 43 static absl::optional<SpsState> ParseSps(const uint8_t* data, size_t length); 44 45 protected: 46 // Parse the SPS state, up till the VUI part, for a buffer where RBSP 47 // decoding has already been performed. 48 static absl::optional<SpsState> ParseSpsUpToVui(BitstreamReader& reader); 49 }; 50 51 } // namespace webrtc 52 #endif // COMMON_VIDEO_H264_SPS_PARSER_H_ 53